Wednesday, November 25

Tactile defensiveness (tactile sensitivity) is a sensory processing disorder in which the affected person experiences hyperarousal and exaggerated sensitivity to touch resulting in great distress and discomfort.

Tactile defensiveness is a sensory disorder of the midbrain region wherein the filtering of the incoming stimuli is affected resulting in exaggerated perception of the touch stimuli.

About 75% of the boys with 'fragile X syndrome' and some girls with full X mutation are found to suffer from tactile sensitivity.

The daily life of the tactile defensiveness affected person becomes very miserable. The daily routines like changing dress, brushing teeth and taking bath become arduous tasks. Some of the reactions of the affected children are as follows.

The tactile defensiveness affected child may be greatly distressed by gentle touch.He may hate being touched on the face.

He may hate coarse clothes. The very feel of the dress on him may distress him.

The tactile defensiveness affected person will dislike anything around the neck like tie, jewellery and shirt collar.

The person with tactile sensory processing disorder may dislike walking bare-footed and the feel of grass, soil or carpet may annoy him.

There can be two forms of tender conditions to touch. The first being the apparent allergic reactions with lesions and inflammations resulting in tender feeling on touch.
This type of tender condition is dealt in detail in the post "causes of skin sensitivity".
On the other hand there may not be apparent damage or reaction on the skin but it may be touch sensitive, having painful tingling sensation and pinprick sensation.
The cause of this could be due to presence of chemicals and their use in cosmetics, detergents and clothing.
Some foods, food products and many food additives cause tactile hypersensitivity.
Sun exposure and environmental damages can cause the tender and painful feeling.
Hormonal effects and hereditary causes also can cause tactile sensitivity.
Certain health disorders, deficiencies and diseases can also give rise tender feeling to touch.

The deficiencies of thiamine (vitamin B1), biotin (vitamin B7) pyridoxine (vitamin B6) and riboflavin (vitamin B2) have been found to cause hypersensitivity with varied signs like tingling, pin prick and stabbing and painful sensation. Supplementation with vitamins has been effective in the control of these symptoms.

Diabetes if untreated can cause neuropathy. Diabetic neuropathy affects all peripheral nerves. It can cause skin to be sore and sensitive to touch. There may be even burning and electric pain.Migraine apart from being a big bother can also give rise to allodynia (a painful condition of skin being sensitive to touch) and very normal activities like combing can give rise to intense pain.

Herpes zoster is a viral disease and causes blisters with mild to extreme pain with tingling, stinging, aching, stabbing and throbbing sensation. After the resolution of the attack the lesion area will be very painful for many days to come.

Fibromyalgia (the cause of which is still under debate) can also cause pain and sensitivity of skin to touch. The affected persons feel widespread painful skin, allodynia (increased response to pressure) and tingling sensation. The skin may appear normal visually, but becomes highly sensitive to touch.

Peripheral neuropathy is the condition wherein the nerves of the peripheral nervous system are damaged. There are various causes for this condition. Peripheral neuropathy causes skin to be very sensitive with symptoms like pain, tingling, crawling, itching and pins and needles sensations. Pain can become very intense. The affected person becomes so hypersensitive that he cannot stand anything touching certain parts of his body especially his feet.

Demyelineating disorders can give rise to sensitive touch. There are a number of causes for the occurrence. Myelin sheath around the nerve fibre is destroyed in this ailment. Paresthesias (sensation of tingling, pricking or stabbing) of the limbs are experienced by the affected persons.

Tactile defensiveness (sensory processing disorder) is a neurological disorder in the the midbrain region. The stimuli are not properly evaluated and filtered by the brain resulting in exaggerated feeling of touch making the affected person distressed and uncomfortable. The affected person may not tolerate slightest pressure on the skin.
Sudden appearance of tender feeling to touch can be a hint of progressive damage to the peripheral nerves or even the spinal cord and the brain.

Tuesday, November 10

Skin sensitivity

It is a condition wherein a person experiences blown up response of skin to certain stimuli.

A myriad of reactions are experienced by persons with skin sensitivity like, lesions, inflammations, bumps and raised spots, pustules and red and raw spots. They may also experience pain, stinging, numbness and burning sensations on the skin.

Causes of skin sensitivity

Sensitivity of skin is caused by many unknown factors. Among the known factors environment, food, race, age, gender and genetic predisposition play a greater part.
The list of possible causative agents (allergens) and causes is exhaustive. A few of the causes are listed below:

Long exposure to sunlight can be a cause

Long exposure to heat

Long exposure to cold and cold winds

High humidity can be a cause

Very dry conditions

Heated dry air inside the house in winter

Salts from sea water and sea-breeze

Exposure to radiation and radiotherapy

Dust, dust mites and dander of pets

Chemicals in cosmetics

Chemicals added to food products and preservatives

Certain types of foods

Flowers and pollen

Medicines and formulations

Chemotherapy

Chemicals in paints and varnish

Formalin and formaldehyde present in products around us

Pesticides

Antibiotics

fungicides

plastics, polymers, resins, adhesives, lacquers and rubber

Contact with metals like, gold, silver, nickel, copper etc...

Alkali in the daily-use products

Acids in the daily-use products

Manifestations of skin sensitivity

The most common manifestation is eczema or dermatitis. This may lead to itchy lesions which may be dry, scaly and thickened or wet itchy lesions which may be raw and blistered.

Contact dermatitis, a condition of sensitivity, causes lesion on contact with allergy causing substance (allergen) and is usually localized rash. Mostly surface regions (epidermis) is affected.
This causes itchy and burning inflammation which may take several days for resolving after the removal of the irritant.

Seborrhoeic dermatitis (seborrhoeic eczema) is skin condition caused by unknown factors. This results in red, itchy, scaly and sensitivity and mostly of the scalp and chest are affected.

Soaps, detergents, hormones and genetic and environmental factors have been found to trigger the rash. In some cases involvement of the fungus Malassezia furfur has been noticed. Excessive intake of vitamin A in children has been associated with this rash. Deficiency of B vitamins like biotin, pyridoxine and riboflavin has been found to cause seborrhoeic dermatitis and sensitivity.

Atopic dermatitis is chronic, itchy, relapsing and non-contagious inflammation. Though the exact cause is not known factors like food, chemicals and environment have been found to trigger the rash or worsen the existing condition. The inner side skin of the elbows and knees is the most affected.

Migraine affected people have been found to suffer from severe skin pain (cutaneous allodynia). Areas of skin which are subjected slight pressure or scratch are sometimes found to give intense pain in persons with migraine and in some cases scratching may trigger migraine.

Though skin sensitivity cannot be completely prevented, steps can be taken to lessen the situation by mitigating the possible causes.

Human skin senses

In humans, pain (including itch), cold, warm and touch (including light pressure, deep pressure, vibration and tickle) are perceived by different nerve endings. Skin, the largest and most exposed organ of human body, is endowed with numerous sensory nerve endings.

One square centimeter of human dermis has up to fifty receptor endings for pain, cold, warm and touch. These nerve endings can perceive one or more of senses like touch, pressure, cold, warm and pain. Some areas like tip of the fingers, lips and tongue have more touch receptor endings in human body. There are many types of nerve receptor endings in human skin having specific functions of senses.

Ruffini endings

Ruffini corpuscle is a slowly adapting mechanoreceptor existing in the human subcutaneous tissues.

This receptor is spindle shaped and perceives the stimulus of stretch and touch.

It monitors the slippage along the skin and helps the mechanism of gripping a object.

These types are extracted from the fruits by physical methods and no chemical method is used.

They are the products of first pressing and about 90% of the olive oil is removed at this stage.

To qualify to be called extra virgin, these varieties must not contain more than 0.8% acidity.Extra virgin types must also have good taste, flavour and aroma.

These varieties are used directly at the table to enhance the flavour of soups, salads and stews and also for dipping.

Premium extra virgin is the finest of the types and contains less than 0.2% acidity.

These types appear yellow to deep green in color and have extra superior flavour with fruity taste.

Virgin olive oil

These types are also produced by the mechanical methods and of the first pressing only.

However these varieties contains extra acidity up to 2%. The rise in acidity when compared to extra virgin varieties may be due to the stage of ripeness of the fruits, the time lapse between the harvest and extraction, the variety of cultivar and the geographic region of the product. It must also have good taste and flavour.

Finer types must contain not more than 1.5% of acidity and should have good flavour.

Refined olive oil

The products which do not qualify to be of higher grades like extra virgin, due to higher and extra acidity are processed further by filtration, heat and chemicals to lower the acidity to 0.3% and remove other defects.

Much of the taste and flavour may be lost. However it is to be noted that solvent extraction method is not involved. This is used in restaurants and in cooking.

Pure olive oil

These types are blends of virgin and refined products.

By addition of virgin olive oil (20%), taste and aroma are infused into the refined product without extra fatty acid percentage (less than 1.5%).

This is priced lesser and hence used in cooking and in restaurants.

Immature fruits

Pomace olive oil

By further processing the paste, these lowest types are extracted by treatment with heat and solvents. Blending with virgin olive oil may be done.

But this product is denoted as pomace olive oil. Its acidity should not exceed 1.5%. It is used commercially for making various by-products.